GRAZING MANAGEMENT AND FACIAL ECZEMA

IN THE late summer and early autumn, farmers in many parts of the North Island and the most northern areas of the South Island are on their guard against facial eczema. This disease, which occurs in both sheep and cattle, is virtually confined to New Zealand, although isolated outbreaks have been reported in Australia. It was first recorded in New Zealand in 1897 (Gilruth, 1897) and since then there have been several widespread and severe outbreakse. g., in 1908, 1910, 1935. 1938, 1955 and 1956. It has been known for many years that the irritation of exposed lightly pigmented skin surfaces -the typical clinical svmptoms of the disease - is the result of liver damage. The search for this liver-damaging factor (Johns and Filmer, 1960) ; the discovery of the fungus Pithomyces chartarum a.s the primary cause of facial eczema (Thornton and Percival, 1959) ; and the isolation from it of the toxin Spnridesmin (Synge and White, 1959) is well documented.